Preserved pharmacokinetics and pharmacodynamics of insulin degludec and liraglutide when administered as insulin degludec/liraglutide in a Chinese population.

We report the findings of a single-dose, randomized, three-period cross-over, clinical trial in healthy Chinese individuals (n = 24) comparing the pharmacokinetics of insulin degludec/liraglutide (IDegLira) with its individual components. Furthermore, we report a population pharmacokinetic analysis of a 26-week, phase III, treat-to-target, randomized trial of 720 Chinese individuals with type 2 diabetes. Participants were randomized to IDegLira, degludec or liraglutide, all once daily with metformin. The pharmacokinetic profiles of IDegLira were similar to its individual components. Dose proportionality was indicated for both IDegLira components. Although there were no relevant covariate effects on degludec exposure, liraglutide exposure was inversely correlated with bodyweight. In conclusion, for the Chinese population, the pharmacokinetics of the fixed-ratio combination IDegLira is similar to that of its individual components.

Levels of circulating semaglutide determine reductions in HbA1c and body weight in people with type 2 diabetes.

Glucagon-like peptide-1 receptor agonists (GLP-1RA) are used for the treatment of type 2 diabetes. Whether clinically important responses and adverse events (AEs) are dependent on the route of administration has not been determined. We demonstrate that nearly identical exposure-response pharmacodynamic relationships are determined by plasma semaglutide levels achieved through oral versus injectable administration for changes in HbA1c, body weight, biomarkers of cardiovascular risk, and AEs such as nausea and vomiting. At typical exposure levels for oral semaglutide, the estimated response is 1.58% (oral) versus -1.62% (subcutaneous) for HbA1c and 3.77% (oral) versus 3.48% (subcutaneous) reduction in body weight relative to baseline after 6 months. Increased body weight is the most important variable associated with reduced semaglutide exposure for both formulations. Hence, interindividual variation in GLP-1R responsivity or route of administration are not major determinants of GLP-1RA effectiveness in the clinic.

Clinical Pharmacokinetics of Oral Semaglutide: Analyses of Data from Clinical Pharmacology Trials.

OBJECTIVE: The absorption, distribution and elimination of oral semaglutide, the first oral glucagon-like peptide-1 receptor agonist for treating type 2 diabetes, was investigated using a population pharmacokinetic model based on data from clinical pharmacology trials. METHODS: A previously developed, two-compartment pharmacokinetic model, based on subcutaneous and intravenous semaglutide, was extended to include data from six oral semaglutide trials conducted in either healthy volunteers or subjects with renal or hepatic impairment. Five trials employed multiple doses of oral semaglutide (5-10 mg) and one was a single-dose (10 mg) trial. In a separate analysis, the model was re-estimated using data from a trial in subjects with type 2 diabetes. RESULTS: The model accurately described concentration profiles across trials. Post-dose fasting time, co-ingestion of a large water volume, and body weight were the most important covariates affecting semaglutide exposure. Bioavailability was 0.8% when oral semaglutide was dosed using the recommended dosing conditions (30 min post-dose fasting time, administered with ≤ 120 mL of water), increasing with a longer post-dose fasting time and decreasing with higher water volume. Within-subject variability in bioavailability was 137%, which with once-daily dosing and a long half-life translates into 33% within-subject variability in steady-state exposure. There was no significant difference in oral bioavailability of semaglutide in healthy subjects and subjects with type 2 diabetes. CONCLUSIONS: The updated model provided a general characterisation of semaglutide pharmacokinetics following oral, subcutaneous and intravenous administration in healthy subjects and subjects with type 2 diabetes. Within-individual variation of oral bioavailability was relatively high, but reduced considerably at steady state. CLINICALTRIALS. GOV IDENTIFIERS: NCT01572753, NCT01619345, NCT02014259, NCT02016911, NCT02249871, NCT02172313, NCT02877355.

Population Pharmacokinetics of Semaglutide for Type 2 Diabetes.

INTRODUCTION: The aim of the present analysis was to characterise the absorption, distribution and elimination of semaglutide by means of population pharmacokinetic (PK) models using data from nine clinical pharmacology trials conducted in both healthy subjects and those with type 2 diabetes. METHODS: Data were obtained from trials with subcutaneous and intravenous administration of semaglutide that utilised frequent PK sampling and included a total of 353 subjects with 10,573 concentration values. RESULTS: Semaglutide PK properties across trials, drug product strengths and populations were well characterised by a two-compartment model with first-order absorption and elimination. For a typical subject with type 2 diabetes, clearance was estimated to be 0.0348 L/h [95% confidence interval (CI) 0.0327-0.0369 L/h], and the central and peripheral volumes were estimated to be 3.59 L (95% CI 3.28-3.90 L) and 4.10 L (95% CI 3.78-4.42 L), respectively (i.e. a total volume of distribution of 7.7 L). Interindividual variation was low (~ 15%) for both clearance and volumes of distribution, with low residual error (< 5%). Clearance and the total volume of distribution were approximately proportional to body weight. Minor differences were identified between healthy subjects and subjects with type 2 diabetes with respect to clearance and absorption rate, and between injection sites with respect to bioavailability. CONCLUSIONS: A novel two-compartment model was developed to provide the general characteristics of semaglutide absorption following subcutaneous administration, and of distribution and elimination across administration routes. Semaglutide PK was shown to be predictable across populations and administration routes and within subjects, and was primarily influenced by body weight. FUNDING: Novo Nordisk, Bagsværd, Denmark.

Exposure-response analysis for evaluation of semaglutide dose levels in type 2 diabetes.

AIMS: To evaluate dose levels for semaglutide, a glucagon-like peptide-1 analogue approved for the treatment of type 2 diabetes, by examining the effects of demographic factors on efficacy and safety in an exposure-response analysis. METHODS: We analysed data from 1552 adults from four randomized phase III trials of 30 to 56 weeks' duration, investigating once-weekly semaglutide doses 0.5 and 1.0 mg. Exposure-response relationships were investigated using graphical and model-based techniques to assess the two dose levels and subgroups with the highest and lowest exposure and response. RESULTS: The population had the following demographic characteristics: baseline mean age between 53.2 and 58.4 years, glycated haemoglobin (HbA1c) between 64 and 67 mmol/mol (8.0% and 8.3%), body weight between 71.3 and 96.2 kg, and diabetes duration between 4.2 and 8.9 years. Exposure-response analysis showed a clear HbA1c and weight reduction across exposures after 30 weeks, irrespective of baseline values. The exposure-response for HbA1c was influenced by baseline HbA1c, and body weight exposure-response was influenced by sex, with limited impact of other factors. Analyses for relevant subgroups of baseline body weight, baseline HbA1c and sex indicated clinically relevant additional benefits with regard to HbA1c and weight with 1.0 vs 0.5 mg semaglutide. The proportion of participants reporting gastrointestinal (GI) side effects increased with increasing exposure, but was counteracted by tolerance development. CONCLUSIONS: The analysis showed that all subgroups obtained a clinically relevant benefit with semaglutide 0.5 mg and an additional benefit with semaglutide 1.0 mg. The increase in GI side effects with higher exposure was mitigated by gradually increasing the dose.

Mathematical Modelling of Glucose-Dependent Insulinotropic Polypeptide and Glucagon-like Peptide-1 following Ingestion of Glucose.

The incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), play an important role in glucose homeostasis by potentiating glucose-induced insulin secretion. Furthermore, GLP-1 has been reported to play a role in glucose homeostasis by inhibiting glucagon secretion and delaying gastric emptying. As the insulinotropic effect of GLP-1 is preserved in patients with type 2 diabetes (T2D), therapies based on GLP-1 have been developed in recent years, and these have proven to be efficient in the treatment of T2D. The endogenous secretion of both GIP and GLP-1 is stimulated by glucose in the small intestine, and the release is dependent on the amount. In this work, we developed a semimechanistic model describing the release of GIP and GLP-1 after ingestion of various glucose doses in healthy volunteers and patients with T2D. In the model, the release of both hormones is stimulated by glucose in the proximal small intestine, and no differences in the secretion dynamics between healthy individuals and patients with T2D were identified after taking differences in glucose profiles into account.

Impact of demographics and disease progression on the relationship between glucose and HbA1c.

CONTEXT: Several studies have shown that the relationship between mean plasma glucose (MPG) and glycated haemoglobin (HbA1c) may vary across populations. Especially race has previously been referred to shift the regression line that links MPG to HbA1c at steady-state (Herman & Cohen, 2012). OBJECTIVE: To assess the influence of demographic and disease progression-related covariates on the intercept of the estimated linear MPG-HbA1c relationship in a longitudinal model. DATA: Longitudinal patient-level data from 16 late-phase trials in type 2 diabetes with a total of 8927 subjects was used to study covariates for the relationship between MPG and HbA1c. The analysed covariates included age group, BMI, gender, race, diabetes duration, and pre-trial treatment. Differences between trials were taken into account by estimating a trial-to-trial variability component. PARTICIPANTS: Participants included 47% females and 20% above 65years. 77% were Caucasian, 9% were Asian, 5% were Black and the remaining 9% were analysed together as other races. ANALYSIS: Estimates of the change in the intercept of the MPG-HbA1c relationship due to the mentioned covariates were determined using a longitudinal model. RESULTS: The analysis showed that pre-trial treatment with insulin had the most pronounced impact associated with a 0.34% higher HbA1c at a given MPG. However, race, diabetes duration and age group also had an impact on the MPG-HbA1c relationship. CONCLUSION: Our analysis shows that the relationship between MPG and HbA1c is relatively insensitive to covariates, but shows small variations across populations, which may be relevant to take into account when predicting HbA1c response based on MPG measurements in clinical trials.

Pharmacokinetic Properties of Liraglutide as Adjunct to Insulin in Subjects with Type 1 Diabetes Mellitus.

BACKGROUND: The pharmacokinetic properties of liraglutide, a glucagon-like peptide-1 receptor agonist approved for the treatment of type 2 diabetes mellitus (T2D), have been established in healthy individuals and subjects with T2D. Liraglutide has been under investigation as adjunct treatment to insulin in type 1 diabetes mellitus (T1D). This single-center, double-blind, placebo-controlled, crossover, clinical pharmacology trial is the first to analyze the pharmacokinetic properties of liraglutide as add-on to insulin in T1D. METHODS: Subjects (18-64 years; body mass index 20.0-28.0 kg/m2; glycated hemoglobin ≤9.5 %) were randomized 1:1:1 to 0.6, 1.2, or 1.8 mg liraglutide/placebo. Each group underwent two 4-week treatment periods (liraglutide then placebo or placebo then liraglutide) separated by a 2- to 3-week washout. Both trial drugs were administered subcutaneously, once daily, as adjunct to insulin. A stepwise hypoglycemic clamp was performed at the end of each treatment period (data reported previously). Pharmacokinetic endpoints were derived from liraglutide concentration-time curves after the final dose and exposure was compared with data from previous trials in healthy volunteers and subjects with T2D. RESULTS: The pharmacokinetic properties of liraglutide in T1D were comparable with those observed in healthy volunteers and subjects with T2D. Area under the steady-state concentration-time curve (AUC) and maximum plasma concentration data were consistent with dose proportionality of liraglutide. Comparison of dose-normalized liraglutide AUC suggested that exposure in T1D, when administered with insulin, is comparable with that observed in T2D. CONCLUSIONS: Liraglutide, administered as adjunct to insulin in subjects with T1D, shows comparable pharmacokinetics to those in subjects with T2D. ClinicalTrials.gov Identifier: NCT01536665.

Liraglutide in Type 2 Diabetes Mellitus: Clinical Pharmacokinetics and Pharmacodynamics.

Liraglutide is an acylated glucagon-like peptide-1 analogue with 97 % amino acid homology with native glucagon-like peptide-1 and greatly protracted action. It is widely used for the treatment of type 2 diabetes mellitus, and administered by subcutaneous injection once daily. The pharmacokinetic properties of liraglutide enable 24-h exposure coverage, a requirement for 24-h glycaemic control with once-daily dosing. The mechanism of protraction relates to slowed release from the injection site, and a reduced elimination rate owing to metabolic stabilisation and reduced renal filtration. Drug exposure is largely independent of injection site, as well as age, race and ethnicity. Increasing body weight and male sex are associated with reduced concentrations, but there is substantial overlap between subgroups; therefore, dose escalation should be based on individual treatment outcome. Exposure is reduced with mild, moderate or severe renal or hepatic impairment. There are no clinically relevant changes in overall concentrations of various drugs (e.g. paracetamol, atorvastatin, griseofulvin, digoxin, lisinopril and oral combination contraceptives) when co-administered with liraglutide. Pharmacodynamic studies show multiple beneficial actions with liraglutide, including improved fasting and postprandial glycaemic control (mediated by increased insulin and reduced glucagon levels and minor delays in gastric emptying), reduced appetite and energy intake, and effects on postprandial lipid profiles. The counter-regulatory hormone response to hypoglycaemia is largely unaltered. The effects of liraglutide on insulin and glucagon secretion are glucose dependent, and hence the risk of hypoglycaemia is low. The pharmacokinetic and pharmacodynamic properties of liraglutide make it an important treatment option for many patients with type 2 diabetes.

Ethnic differences in insulin sensitivity, ß-cell function, and hepatic extraction between Japanese and Caucasians: a minimal model analysis.

CONTEXT: Ethnic differences have previously been reported for type 2 diabetes. OBJECTIVE: We aimed at assessing the potential differences between Caucasian and Japanese subjects ranging from normal glucose tolerance (NGT) to impaired glucose tolerance (IGT) and to type 2 diabetes. DESIGN: This was a cross-sectional study with oral glucose tolerance tests to assess ß-cell function, hepatic insulin extraction, and insulin sensitivity. PARTICIPANTS: PARTICIPANTS included 120 Japanese and 150 Caucasian subjects. MAIN OUTCOMES: Measures of ß-cell function, hepatic extraction, and insulin sensitivity were assessed using C-peptide, glucose, and insulin minimal models. RESULTS: Basal ß-cell function (Φ(b)) was lower in Japanese compared with Caucasians (P < .01). In subjects with IGT, estimates of the dynamic (Φ(d)) and static (Φ(s)) ß-cell responsiveness were significantly lower in the Japanese compared with Caucasians (P < .05). In contrast, values of insulin action showed higher sensitivity in the Japanese IGT subjects. Hepatic extraction was similar in NGT and IGT groups but higher in Japanese type 2 diabetic subjects (P < .01). Despite differences in insulin sensitivity, ß-cell function, and hepatic extraction, the disposition indices were similar between the 2 ethnic groups at all glucose tolerance states. Furthermore, the overall insulin sensitivity and ß-cell responsiveness for all glucose tolerance states were similar in Japanese and Caucasians after accounting for differences in body mass index. CONCLUSION: Our study provides evidence for a similar ability of Japanese and Caucasians to compensate for increased insulin resistance.

Modeling of 24-hour glucose and insulin profiles in patients with type 2 diabetes mellitus treated with biphasic insulin aspart.

Insulin therapy for diabetes patients is designed to mimic the endogenous insulin response of healthy subjects and thereby generate normal blood glucose levels. In order to control the blood glucose in insulin-treated diabetes patients, it is important to be able to predict the effect of exogenous insulin on blood glucose. A pharmacokinetic/pharmacodynamic model for glucose homoeostasis describing the effect of exogenous insulin would facilitate such prediction. Thus the aim of this work was to extend the previously developed integrated glucose-insulin (IGI) model to predict 24-hour glucose profiles for patients with Type 2 diabetes following exogenous insulin administration. Clinical data from two trials were included in the analysis. In both trials, 24-hour meal tolerance tests were used as the experimental setup, where exogenous insulin (biphasic insulin aspart) was administered in relation to meals. The IGI model was successfully extended to include the effect of exogenous insulin. Circadian variations in glucose homeostasis were assessed on relevant parameters, and a significant improvement was achieved by including a circadian rhythm on the endogenous glucose production in the model. The extended model is a useful tool for clinical trial simulation and for elucidating the effect profile of new insulin products.

Body composition is the main determinant for the difference in type 2 diabetes pathophysiology between Japanese and Caucasians.

OBJECTIVE This cross-sectional clinical study compared the pathophysiology of type 2 diabetes in Japanese and Caucasians and investigated the role of demographic, genetic, and lifestyle-related risk factors for insulin resistance and ß-cell response. RESEARCH DESIGN AND METHODS A total of 120 Japanese and 150 Caucasians were enrolled to obtain comparable distributions of high/low BMI values across glucose tolerance states (normal glucose tolerance, impaired glucose tolerance, and type 2 diabetes), which were assessed by oral glucose tolerance tests. BMI in the two cohorts was distributed around the two regional cutoff values for obesity. RESULTS Insulin sensitivity was higher in Japanese compared with Caucasians, as indicated by the homeostatic model assessment of insulin resistance and Matsuda indices, whereas ß-cell response was higher in Caucasians, as measured by homeostatic model assessment of ß-cell function, the insulinogenic indices, and insulin secretion ratios. Disposition indices were similar for Japanese and Caucasians at all glucose tolerance states, indicating similar ß-cell response relative to the degree of insulin resistance. The main determinants for differences in metabolic indices were measures of body composition, such as BMI and distribution of adipose tissue. Differences in ß-cell response between Japanese and Caucasians were not statistically significant following adjustment by differences in BMI. CONCLUSIONS Our study showed similar disposition indices in Japanese and Caucasians and that the major part of the differences in insulin sensitivity and ß-cell response between Japanese and Caucasians can be explained by differences in body composition.

Dosing rationale for liraglutide in type 2 diabetes mellitus: a pharmacometric assessment.

The glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide was approved in 2010 by the US Food and Drug Administration (FDA) as an adjunct treatment to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. This article provides insights into the use of pharmacometric analyses for regulatory review with a focus on the dosing recommendations. The assessment was based on the totality of exploratory and confirmatory analysis of dose-finding and pivotal clinical data and was structured around a set of key questions in accordance with current FDA review practice. For the pharmacometric review of liraglutide, the key questions focused on exposure-response relationships for effects on fasting plasma glucose, hemoglobin A(1c), and calcitonin and on variability in exposure across demographic subgroups of patients. The importance of conducting exploratory exposure-response analysis and population pharmacokinetic studies in clinical drug development to support dosing recommendations is highlighted.

Mechanism-based population modelling for assessment of L-cell function based on total GLP-1 response following an oral glucose tolerance test.

GLP-1 is an insulinotropic hormone that synergistically with glucose gives rise to an increased insulin response. Its secretion is increased following a meal and it is thus of interest to describe the secretion of this hormone following an oral glucose tolerance test (OGTT). The aim of this study was to build a mechanism-based population model that describes the time course of total GLP-1 and provides indices for capability of secretion in each subject. The goal was thus to model the secretion of GLP-1, and not its effect on insulin production. Single 75 g doses of glucose were administered orally to a mixed group of subjects ranging from healthy volunteers to patients with type 2 diabetes (T2D). Glucose, insulin, and total GLP-1 concentrations were measured. Prior population data analysis on measurements of glucose and insulin were performed in order to estimate the glucose absorption rate. The individual estimates of absorption rate constants were used in the model for GLP-1 secretion. Estimation of parameters was performed using the FOCE method with interaction implemented in NONMEM VI. The final transit/indirect-response model obtained for GLP-1 production following an OGTT included two stimulation components (fast, slow) for the zero-order production rate. The fast stimulation was estimated to be faster than the glucose absorption rate, supporting the presence of a proximal-distal loop for fast secretion from L: -cells. The fast component (st3) = 8.64·10⁻5 [mg⁻¹]) was estimated to peak around 25 min after glucose ingestion, whereas the slower component (st4 = 26.2·10⁻5 [mg⁻¹]) was estimated to peak around 100 min. Elimination of total GLP-1 was characterised by a first-order loss. The individual values of the early phase GLP-1 secretion parameter (st3) were correlated (r = 0.52) with the AUC(0-60 min.) for GLP-1. A mechanistic population model was successfully developed to describe total GLP-1 concentrations over time observed after an OGTT. The model provides indices related to different mechanisms of subject abilities to secrete GLP-1. The model provides a good basis to study influence of different demographic factors on these components, presented mainly by indices of the fast- and slow phases of GLP-1 response.

Population pharmacokinetics of liraglutide, a once-daily human glucagon-like peptide-1 analog, in healthy volunteers and subjects with type 2 diabetes, and comparison to twice-daily exenatide.

The once-daily human glucagon-like peptide-1 (GLP-1) analog, liraglutide, was recently shown to provide improved glycemic control in subjects with type 2 diabetes (T2D) compared with exenatide. The aim of this work is to estimate the population pharmacokinetics of liraglutide and make a comparison to the pharmacokinetic profile of exenatide. Pharmacokinetic data from 5 published studies of subcutaneous and intravenous administration of liraglutide to healthy volunteers (HV) and subjects with T2D were used to develop a population pharmacokinetic model in NONMEM. Exenatide data came from a published study in T2D. Liraglutide pharmacokinetics were adequately described using a 1-compartment model with sequential zero- and first-order absorption. The pharmacokinetic profile of once-daily liraglutide showed considerably smaller peak-to-trough fluctuations compared with twice-daily exenatide. A small difference in the estimates of absorption parameters was found between HV and subjects with T2D but was not clinically relevant. It was concluded that pharmacokinetic profiles estimated by modeling showed that liraglutide has pharmacokinetic properties consistent with once-daily dosing in humans and provides better pharmacokinetic coverage in comparison with twice-daily exenatide. Furthermore, no clinically relevant differences were found in liraglutide pharmacokinetics between HV and subjects with T2D.

Predictive performance for population models using stochastic differential equations applied on data from an oral glucose tolerance test.

Several articles have investigated stochastic differential equations (SDEs) in PK/PD models, but few have quantitatively investigated the benefits to predictive performance of models based on real data. Estimation of first phase insulin secretion which reflects beta-cell function using models of the OGTT is a difficult problem in need of further investigation. The present work aimed at investigating the power of SDEs to predict the first phase insulin secretion (AIR (0-8)) in the IVGTT based on parameters obtained from the minimal model of the OGTT, published by Breda et al. (Diabetes 50(1):150-158, 2001). In total 174 subjects underwent both an OGTT and a tolbutamide modified IVGTT. Estimation of parameters in the oral minimal model (OMM) was performed using the FOCE-method in NONMEM VI on insulin and C-peptide measurements. The suggested SDE models were based on a continuous AR(1) process, i.e. the Ornstein-Uhlenbeck process, and the extended Kalman filter was implemented in order to estimate the parameters of the models. Inclusion of the Ornstein-Uhlenbeck (OU) process caused improved description of the variation in the data as measured by the autocorrelation function (ACF) of one-step prediction errors. A main result was that application of SDE models improved the correlation between the individual first phase indexes obtained from OGTT and AIR (0-8) (r = 0.36 to r = 0.49 and r = 0.32 to r = 0.47 with C-peptide and insulin measurements, respectively). In addition to the increased correlation also the properties of the indexes obtained using the SDE models more correctly assessed the properties of the first phase indexes obtained from the IVGTT. In general it is concluded that the presented SDE approach not only caused autocorrelation of errors to decrease but also improved estimation of clinical measures obtained from the glucose tolerance tests. Since, the estimation time of extended models was not heavily increased compared to basic models, the applied method is concluded to have high relevance not only in theory but also in practice.

Pharmacodynamic model of interleukin-21 effects on red blood cells in cynomolgus monkeys.

Interleukin-21 (IL-21) is a novel cytokine that is currently under clinical investigations as a potential anti-cancer agent. Like many other anti-cancer agents, including other interleukins, IL-21 is seen to produce a broad range of biological effects that may be related to both efficacy and safety of treatment. The present analysis investigates the observed pharmacodynamics effects on red blood cells following various treatment schedules of human IL-21 administrated to cynomolgus monkeys. These effects are described by a novel non-linear mixed-effects model that enabled separation of drug effects and sampling effects, the latter believed to be due partly to blood loss and partly to stress induced haemolysis in connection with blood sampling. Two different studies with a total of 9 different treatment groups of cynomolgus monkeys were used for model development. In conclusion, the model describes the IL-21 induced drop in red blood cells to be (1) caused by removal rather than suppression of production, consistent with increased reticulocyte concentration, and (2) considerably delayed compared to dosing, i.e. not related to the drop in red blood cells observed immediately post dose. It is believed that the structural model presented here can be used for other types of drug induced loss of red blood cells, whereas the mechanism for sampling related blood loss is relevant for investigations of anaemia in all pharmacological studies with smaller animals.

Pharmacokinetic and pharmacodynamic properties of insulin aspart and human insulin.

The preferred approach to determine the pharmacokinetic (PK) and pharmacodynamic (PD) properties of insulin analogues is the euglycemic glucose clamp. Currently non-compartmental data analytical approaches are used to analyze data. The purpose of the present study is to propose a novel compartmental-model for analysis of data from glucose clamp studies. Data used in this trial only involved 18 of the 20 originally treated subjects. Data was obtained from a crossover trial where 18 healthy subjects each received a single subcutaneous (s.c.) dose of 1.2 nmol/kg (body weight) insulin aspart (IAsp) or 1.2 nmol/kg human insulin (HI) during a euglycemic glucose clamp after overnight fast. Serum insulin and glucose concentrations were measured and the glucose infusion rate (GIR) was adjusted after dosing, to maintain blood glucose near basal levels. Individual model parameters were estimated for IAsp, HI, and the corresponding glucose and GIR data. We found statistically significant differences between most of the HI and IAsp pharmacokinetic parameters, including the sigmoidicity of the time course of absorption (1.5 for HI vs. 2.1 for IAsp (unit less), P = 0.0005, Wilcoxon Signed-rank test), elimination rate constant (0.010 min-1 for HI vs. 0.016 min-1 for IAsp (P = 0.002)). The PD model parameters were mostly not different, except for the rate of insulin action (0.012 min-1 for HI vs. 0.017 min-1 for IAsp (P = 0.03)). The model may provide a framework to account for different PK properties when estimating the PD properties of insulin and insulin analogues in glucose clamp experiments.

Safety and pharmacokinetics of ReN1869: a first human dose study in healthy subjects after single-dose administration.

ReN1869 (NNC 05-1869) is a novel, selective H1 receptor antagonist that has been developed for analgesic purposes. In a first human dose administration study, the safety and pharmacokinetics of seven single oral doses in the range of 3.5 to 95 mg ReN1869 were studied. The study was a randomized, double-blind, placebo-controlled, dose-escalating study in 56 healthy subjects. No serious or severe adverse events were reported. After active doses, an average of 0.6 adverse events (AEs) was reported per subject in comparison to 0.5 AEs per subject after placebo, and the frequency of subjects reporting AEs was not related to dose level. The most frequently reported adverse events were dizziness, fatigue, and somnolence, and their occurrence was not proportional to dose. Vital signs, ECG recordings, and clinical laboratory results showed no changes of clinical relevance. During telemetric monitoring at all dose levels until 4 hours after dosing, no clinically relevant abnormalities were observed. A maximally tolerated dose was not identified. ReN1869 was rapidly absorbed after dosing. The overall mean value of t1/2 and oral clearance was 4.7 hours and 11.7 L/h, respectively. The parameters Cmax and AUC increased proportionally with dose level, whereas all other pharmacokinetic parameters were independent of the dose. In conclusion, single-dose administration of ReN1869 in doses up to 95 mg exhibited very few adverse events and no clinically relevant effects on any of the observed safety parameters. The pharmacokinetics points to simple first-order pharmacokinetics for ReN1869. All together, it makes ReN1869 a potential new drug candidate for the treatment of chronic pain and inflammatory conditions of neurogenic origin.

Non-linear mixed effects modeling of sparse concentration data from rats: application to a glycogen phosphorylase inhibitor.

We investigated the use of non-linear mixed effects modeling in two preclinical studies of the glycogen phosphorylase inhibitor 1,4-dideoxy-1,4-imino-D-arabinitol (DAB). In a 28-day repeated-dose toxicity study rats were dosed once daily p.o. with 0, 20, 45, 100, or 470 mg/kg of DAB in aqueous solutions by oral gavage. Three blood samples were obtained from each animal using a staggered sampling scheme. During the cause of model development, data were included from a safety pharmacological cardiovascular study, in which rats were dosed once orally with 0, 4, 40, or 400 mg/kg of DAB thereby enabling an extension of the dose range of the model. DAB was assayed in plasma using a validated LC/MS/MS method. Non-linear mixed effects modeling was performed using the software NONMEM. The covariate analysis comprised dose, sex and time. Exposure results (Cmax, AUC) obtained by mixed effects modeling were compared to results from noncompartmental analysis using naïve pooling of data. The final model was a one-compartment model with first order absorption and a saturation-like dose dependent increase of the (oral) clearance (CL/f) and volume of distribution (V/f). Furthermore, V/f increased (by 55%) from Day 1 to Day 28. The dose dependencies of CL/f and V/f were most likely due to dose dependent decreases of the fraction systemically absorbed (f). The mechanism behind the dose dependencies may be saturation of a (putative) carrier mediated transport or modulation of tight junctions causing a reduced paracellular transport across the intestinal epithelium. Exposure results obtained from the model compared well with results obtained using noncompartmental analysis. An analysis of the data requirements for non-linear mixed effects modeling showed that at least three concentration values per animal were required for model development. We conclude that non-linear mixed effects modeling is feasible even with dose dependent pharmacokinetics in preclinical studies, such as 28-day toxicity studies in rodents. Supplementing data from additional preclinical studies may be required in order to extend the dose range. Non-linear mixed effects models may prove to be valuable tools in early PK and PK-PD modeling during drug development.